BEIJING  As they prepare to host the Olympics — an event whose very purpose is to push the limits of human beings — the Chinese are trying to do what man never has: Control the weather.

With five months to go before the Summer Games come to Beijing, Chinese scientists say they are confident they can keep rain away from the opening ceremony, or summon a storm on cue to clear the city's choking pollution.

It's a bold — and, according to international scientists, dubious — bit of stage managing, even for a nation that has already shown an outsize ambition to use the Olympics to showcase its development from rural poverty to economic powerhouse.

China is spending $40 billion to remake the infrastructure of the ancient capital, and it already spends an estimated $100 million a year and employs 50,000 for rainmaking.

At installations like one called Fragrant Hills, outside Beijing, peasants don military fatigues and helmets and squat behind anti-aircraft guns and rocket launchers, blasting the sky with silver iodide, hoping to shock rain from the clouds.

If rain threatens the opening or closing ceremony, Beijing officials say they will set up several banks of rocket launchers outside the city to seed threatening clouds and cause them to release their rain before it reaches the capital.

"We are now drafting the implementation plan for the artificial rain mitigation for the opening and closing ceremonies," said Wang Yubin, a Beijing Meteorological Bureau engineer. "This is a very complex process, so we must select the right time and place."

China, short on water and arable land, has lavished some of the scarce resources it has on rainmaking and rain prevention.

Its cloud-seeding weapons include 6,781 artillery guns and 4,110 rocket launchers, according to the state-run Xinhua news agency. The China Meteorological Administration says 4,231 flights for cloud-seeding were conducted from 1995 to 2003.

The Chinese scientists say it worked — increasing rainfall during those years by 210 billion cubic meters, enough to meet the annual needs of 400 million people. China has a population of about 1.3 billion.

Other scientists are not so sure.

"I don't think their chances of preventing rain are very high at all," said Roelof Bruintjes, a meteorologist with the U.S. National Center for Atmospheric Research, who was in China several weeks ago and told top-ranking Chinese scientists he was skeptical.

"If there is really a weather system that is producing rain, they won't be able to do anything. We can't chase away a cloud, and nobody can make a cloud, either."

The argument is about much more than precipitation theory. The Olympics, set to run Aug. 8-24, are tightly scheduled, and a rainy day can wreak havoc — particularly if the opening ceremony, perhaps China's best showcase of the games, is a washout.

Besides being one of the warmest months of the year in Beijing, with highs averaging in the mid-80s, August is among the wettest, with about 7 inches of rain in a typical year.

It's not the first time China has mounted a gargantuan project to bend nature. The Three Gorges dam project, spanning the mighty Yangtze River, is the largest hydroelectric undertaking in the world.

But the history of Chinese science projects has its quirky examples, too — like the one that promises to produce softball-size tomatoes or giant gourds by shooting seeds or seedlings into space and then sowing them back on earth.

Fifty years ago, during the Great Leap Forward, Mao Zedong made extravagant claims about new agricultural techniques that could lift China out of starvation. His plans to beat nature were based mostly on ideology and psuedo-science and caused widespread famine.

Andy Detwiler, a professor of meteorology at the South Dakota School of Mines and Technology who edits the Journal of Weather Modification, suggested the Olympic weather-harnassing effort may not meet with much more success.

"It's the emperor and his new clothes sort of thing. Nobody wants to admit there is any uncertainty involved in the operation," he said. "The only nations I know of who claim that they can schedule the weather — clear skies for public events, prevent rain at big celebrations — is the old Soviet Union and China."

On the very day Chinese weather modification experts were boasting at a news conference about controlling rain during the Olympics, the country's midsection was being pummeled by the worst snow storm in 50 years, which Chinese meteorologists failed to predict.

Several calls to the China Meteorological Administration seeking interviews with weather modification officials to discuss the Olympics plans were greeted with the same reply: "This is a sensitive topic." One junior staff member at the Beijing Meteorological Bureau said the subject was very guarded, "like Americans keeping their nuclear secrets."

In an interview with the Associated Press, Wang Guanghe, deputy director of the Research Center for Weather Modification, acknowledged an absence of rigorous science in China's vast cloud-seeding operation.

"We haven't done any of these studies," he said. "We have an indoor simulation model. We can use devices to observe the changes in the clouds ... but it's really hard to have an authentic and convincing result."

A recent study in Oklahoma and Texas uncovered little evidence that cloud seeding works. Like China, many American programs are run by local governments with little coordination from the nation's capital.

"You just don't see any consistent signal that these activities are producing any more rainfall than what normally would have occurred," said Jeff Basara, director of research for the Oklahoma Climatological Survey. "You're much better off conserving water than trying to make it rain."

The most common way to seed clouds is blasting them with silver iodide, which is generally believed to be a safe chemical. Liquid nitrogen and dry ice can also be used.

Another worry: Beijing's severe air pollution. Daniel Rosenfeld, a meteorologist at The Hebrew University of Jerusalem who has visited his Chinese colleagues, said there are early indications that pollution decreases rain, which may be driving Beijing and northern China further into drought.

The International Olympic Committee has already threatened to postpone some endurance events if Beijing's air quality is poor. Beijing, a city of 17 million, is expected to ban 1.5 million vehicles from the roads, shut factories and foundries and halt the city's frantic construction boom for the games.

"The only thing that cleans up the pollution is the rain, and if they are going to suppress rain, my worry is the pollution will be oppressive," said Veerabhadran Ramanathan, an atmospheric scientist at the Scripps Institution of Oceanography at the University of California San Diego, who will use the Olympics to study the impact of reduced pollution. "It's a Catch-22."

To report corrections and clarifications, contact Reader Editor Brent Jones. For publication consideration in the newspaper, send comments to letters@usatoday.com. Include name, phone number, city and state for verification.

An artillery operator stands next to artillery used to seed clouds to induce rain at a Beijing Meteorological Bureau station in Beijing in July 2007. China regularly uses cloud seeding to improve local weather conditions, and plans to use this technique to ensure optimum weather conditions for the 2008 Olympic Games.

By Ng Han Guan, AP File

Conversation guidelines: USA TODAY welcomes your thoughts, stories and information related to this article.
Please stay on topic and be respectful of others. Keep the conversation appropriate for interested readers across the map.